As a kind of run-flat tire that allows a tire to run a predetermined distance without losing the load support function even when the inner pressure of the tire decreases due to puncture or the like, a side-reinforced run-flat tire, whose sidewall portions have improved rigidity, has been proposed (refer to Patent Literature 1, for example). A side-reinforced run-flat tire includes, in the sidewall portions, reinforcing rubber having a relatively high modulus of elasticity and a crescent sectional shape. The reinforcing rubber plays the role of supporting the load of the vehicle during running (run-flat running) where the inner pressure equals atmospheric pressure due to puncture.